Method of making patent, japan, and enamel leathers



Patented @ct. 27, 1931 SAMUEL S. SADTLER, OF SPRINGFIELD TOWNSHIP,MONTGOMERY COUNTY, AND

' EUGENE F. CAYO, F PHILADELPHIA, PENNSYLVANIA METHOD OF MAKING PATENT,JAPAN, AND ENAMEL LEATHERS No Drawing.

This invention has particularly to do with the preparation of leather,particularly that made from horsehide and goat skins, for themanufacture of patent, japan or enamel leather. In the ordinaryprocesses of making such enamel or patent leather, it is customary tosubject the leather skins to a treatment whereby the oils remaining inthe skins, as a result of the previous fat liquoring of the skins in theprocess of making leather, are

usually applied, quite absorbent. Moreover,

the abstractions of these oils involves an additional step in theprocess, lengthens the time required to make patent or enamel leather,and correspondingly increases the cost of making it.

It is one of the objects of the present invention to eliminate this stepof extracting the oils contained in the leather skins or hides and toretain within the skins the oil present therein as the result ofprevious steps in the leather-making processes. A further object of ourinvention is to protect the enamel from anything that would penetratethrough the leather to the flesh side.

A further object of our invention is to reduce the number of steps oftreatment required for producing patent or enamel leather, by making itunnecessary to extract the oils contained in the leather hides or skinsby the naphtha or any other process and to render the flesh side of theleather practically incapable of absorbing the enameling materials.

is softer, thinner, more durable and more flexible than that produced bythe processes heretofore practised.

Application filed March 19, 1927. Serial No. 176,834.

Other objects of our invention will appear in the specification andclaims below.

In carrying out our invention, we take the leather hides or skins asthey come from the leather makers, and containing the oils or oilymaterials usually contained therein and provide that side of the hidewhich is to be enameled with a film of a gum or gum-like material whichis practically not soluble or miscible in the oils of the enamel coatingmaterials to be applied thereto, which film is also flexible andimpervious to water and to grease or oil that is already contained inthe skin or hide, whether such oil be natural, or worked into the skinin the previous process of treating the same.

For the purpose of providing this film we have found that a shellac-likematerial such as (1) a solution of shellac in alcohol or (2) the estersof cellulose are both well ada ted for the purpose, but the former wehave found to be preferable.

In the practice of our invention, we preferably prepare and use asolution of shellac, for instance, ordinary orange shellac in alcohol,and to this solution we add a finely divided filler which is insolublein the alcohol or other solvent of the shellac or other film formingmaterial employed.

The pores or interstices of the leather and particularly on the fleshside of the skin are very absorbent. This filler is for the purpose offilling the pores of such porous surface of the leather with aninsoluble material which will operate to fill or clog up the pores, toprevent the absorption of the shellac solvent into the skin or hide, andto hold the shellac solution on the surface of the skin or hide untilsuch time as the solvent has evaporated, leaving a film of shellac onthe surface or surfaces of the leather so treated.

As an instance of a preferred solution for applying to the leatherbefore enameling but one which may be varied and modified to aconsiderable extent without departing from the spirit and scope of ourinvention, we may use a 5% shellac solution in alcohol. To this we add asuitable filler, which should be without the characteristics of apigment.

This filler may be finely divided, silica, clay,

' I stretched on boards.

aluminum oxid, aluminum hydroxid or barites. We prefer to use acolloidal clay, such as bentonite, which tends to remain. suspended inthe solution, does not appreciably increase the opacity of the film, andfills or clogs up the pores in the desired manner. The use of such aninert filler is particularly desirable. in the treatment of softleather, such as those made from goat skins for the production of a softpatent or enameled leather. To give a desired color to the leather asuitable alcohol-soluble dye may be added to the shellac solution. Sucha dye may be aJnigrosine base, which is developed by the acidity of theshellac.

A suitable compositidn for the practice of our process maybe made of'thefollowing ingredients, thoroughly mixed together, in the followingproportions:

' The leather is prepared for patent leatherlng, enameling or japanningin the usual way,

' except that the step of extracting the oil from the leather skin priorto the ap lication of the enameling or patent leathermg thereto, asheretofore practised, is omitted. The leather skin to be treated isnailed and tightly In the ordinary process of enameling leather, theleather skin, with the oil extracted from the skin is stretched onboards and given a coat of leather enameling material which usuallyconsists of linseed oil, litharge, Prussian blue, lampblack and similaringredients, thinned to proper consistency with light petroleum, and byleather enameling material, we mean material of this character,'which,when applied to flexible material such as leather, is very flexible,tenacious and susceptible of high polish. The first layer or coat isgeneral y applied thick because of the absorbent property or quality ofthe leather, particularly on the flesh side. The first coating or'daubcontains a suitable amount of oil as an essential ingredient, and toprevent this absorbent surface of the leather from absorbing the oil outof the daub and to prevent the leather enameling leather, thecoatingmaterial is made just as thick and dry as it is possible to make it andpermit of its being spread over the surface 'of the leather with aslicker. In carrying out our improved process, however, the leather skinor hide, with the natural oils and greasesin it, is stretched and nailedon the boards and given a thin coating of our shellac solution with thefiller and possibly a color base contained therein as above described,

This coating material is appliedto the surface of the leather in anysuitable and convenient manner but it should thoroughly coat and suchthat it may be sprayed on the surface or applied with a brush. Aftersuch application of the coating material to the leather,

"skin or hide, the coating is allowed to dry by the evaporation of thesolvent, whereuponthe leather so coated with-our said composition abovedescribed, is ready for the leather enameling process.

When the flesh side of the skin is the side to which the leatherenameling is to be ap-v plied, it is to that side that our film ofshellac or similar gum-like material is applied. When the leatherenameling is to be applied to the grain side of the hide of the skin,then our protective film or coating is applied to the grain side of theleather. This film is operative to prevent the first layer of paste orthick enameling material or the oily content thereof from penetratinginto the pores of the leather. It firmly adheres to the film but doesnot substantially penetrate into the hide.

The film having been so applied, the leather is then subjected to theleather enameling process, comprising the application of the first orground coat, of leather enameling material similar to that used informer leather enameling processes but this ground coat may be andpreferably is somewhat thinner than the daub heretofore employed inenameling processes. The film of shellac covers the surface of theleather to which the first coat is applied and is not soluble ormiscible in the oils (which may be boiled linseed oil) contained in thefirst or ground coat. After this first coating has been applied, theleather so coated is placed in a hot stove or oven and allowed to remainthere until the ground coat is thoroughly dried andbaked, whereupon itis then removed from the drier and pumiced smooth. Thereafter, a thinnercoat of similar leather enameling material may be applied andthiscoating may be similarly heated until thoroughly dry. This coating isthen subjected to a similar process of pumicing it smooth, whereupon athin finish coating of japan or copal varnish is applied.

Because of the fact that the film which we have provided'for the skin orleatherfprevents the leather enameling material from penetrating intothe normally porous dry surface of the leather, the first orpriming orground coat of enameling material may be applied in a thinner or morefluid condition to produce I enamel is thinner, and the original leatheris soft and flexible due to the oil and grease content thereof, thepatent or enameled leather made by our improved processes is moreflexible and less liable to crack when the leather is flexed or bentthan the patent leathers made pursuant to prior processes.

The leather of the patent or enameled leather so produced contains andretains much more oil than that present in ordinary patent leather orenameled leather and consequently the finished product will be moreflexible, softer and less liable to crack.

Having thus described our invention, what we claim and desire to protectby Letters Patent of the United States is: Y

1. The process of enameling leathers from which the oils and greasesremaining therein from the leather making processes have not beenremoved, which consists in applying to the surface of said leathercontaining said oils and greases a coat of shellac dissolved in alcoholand mixed with colloidal clay, to fill the pores of the surface of saidleather with particles of clay and to thereby prevent the leather fromabsorbing the solution and to retain the shellac content of the solutionon the surface" of said leather until the solvent shall have evaporated,then enameling said surface by applying successive coatings of patentleather enameling materials and thoroughly heating and drying the sameafter each application thereto of each coating.

2. The method of making leathers from which the oils and greases havenot been extracted, which consists in applying to a surface of saidleather a coating composed of a solution of a flexible shellac-likesubstance insoluble and immiscible in the oils and greases contained insaid leather and insoluble and immiscible in the usual leather enamelingcompositions, said solution containing an inert finely divided fillersuspended'therein and operative to fill the pores of said leather and tothereby prevent the leather from absorbing said solution and alsocontaining a dye soluble in the solvent of said, solution, permittingsaid coating so applied to dry by the evaporation of said solvent, andthen applying thereto successive coatings of patent leather enamelingmaterials and thoroughly heating and drying the same after theapplication of each coating.

3. The method of enameling leathers from which the oils and greasesnormally present in leathers have not been extracted, which consists inapplying to the surface of said leather, a coating comprising a solutionof a flexible shellac-like substance insoluble and immiscible in oilsand greases, and containing an inert filler having substantially npigmental properties and operative to fill th pores of said leather,thereby greatly checking the absorption of said solution into saidleather, permitting the coating so applied to' in said solution finelydivided inert insoluble material operative when applied to clog and fillthe pores of said leather at the surface thereof to prevent the solventof said solution and the gum-like material dissolved therein fromsubstantially penetrating the fibrous material and to hold said gum-likematerial on the surface of said leather until said solvent evaporates,thereby permitting a film of said gum-like material over the surface ofsaid leather and then applying over said film successive coatings ofsuitable patent leather enameling materials and heating each coat tothoroughly dry the same after the application thereof to said leather.

In witness whereof, we have hereunto set our hands this 17th day ofMarch, 1927.

SAMUEL S. SADTLER. EUGENE F. QAYO.

